CHEM Elements, compounds and mixtures

Characteristics of elements

• It is a pure substance

• It is made up of only one kind of atoms

• It can’t be separated into simpler substances

• It is divided into metals, non metals, matalloids, and noble gases

Characteristics of compounds

• It is a pure substance

• It is formed by the combination of two or more different elements

• It can be broken down into its elements by chemical methods only

Characteristics of mixtures

• It is an impure substance

• It is formed by the combination of two or more elements, compounds or both

• It retains the properties of its constituent elements or compound

Element

It is a pure substance made up of only one kind of atoms

Structure of an atom

Atom is the smallest partical of an element which can take part in a chemical reaction. It is divided into

• Nucleus-

  • Protons - positively charged particals.

  • Neutrons - particals having no charge.

• Orbits/Shells/energy levels

  • Electrons - negatively charged particals.

Difference between metals non metals

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Differences between metalloids and noble gases

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Names and symbols of elements

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Molecules

Atoms of the same or different elements combine to form a molecule

Monoatomic molecules

Elements made up of single atoms

Diatomic elements

Elements made up two of atoms

Poly atomic molecules

Elements made up of more that two atoms

Atomicity

The number of atoms of an element that joint together to form a molecule of an element

Molecules of compounds

When two or more atoms of different kinds chemically combine together are called molecules of compounds.

Compound

An pure substance made up of two or more different elements chemically combined together in a fixed proportion

Properties of a compound

• Components in a compound arr in a fixed proportion

• Particals in a compound are of one kind

• Components of a compound have a definite set of properties

• Elements in a compound do not retain their properties

• Components of a compound can be separated by chemical methods only

Differenciate between elements and compound

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Mixtures

It is an impute substance made up of two or more elements or compounss or both combined mechanically in any proportion. A mixture retains the propertirs of its constituents.

Homogeneous mixtures

A mixture in which the constituents are uniformly mixed throughout.

Heterogeneous mixtures

Mixtures inwhich the constitients are not uniformly mixed throughout.

Differences between homogeneous mixtures and heterogeneous mixtures

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Differences between compounds and mixtures

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Name the 4 ways to separate solid-solid mixtures

Separation methods are-

• Sublimation

• Magnetic separation

• Solvent extraction

• Fractional crystillisation

Name the 4 ways to separate solid-liquid mixtures

The separating methods are

• Filteration

• Sedimentation

• Evapouration

• Distillation

Name the 2 methods of separating liquid-liquid methods

The 2 methods of separation are

• Separation funnel

• Fractional disstillation

Name the method to separate liquid gas mixtures

Boiling the liquid gas mixtures

Name the 2 methods of separating gas-gas mixtures

• Diffision

• Solubility in solvent

Name 2 methods used to separate complex mixtures

• Centrifugation

• Cromatography

SUBLIMATION

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MAGNETIC SEPARATION

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SOLVENT EXTRACTION

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FRACTIONAL CRYSTILLISATION

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FILTERATION

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SEPARATING FUNNEL

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EVAPORATION

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DISTILLATION

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SEPARATING FUNNEL

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FRACTIONAL DISTILLATION

CROMATOGRAPHY

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CENTRIFUGATION

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Centrifugal force

A revolving body exerts a force away from the center of rotation called centrifugal force